Various processes occurring in collisions of ions with molecules have been attracting much attention[1].Of particular interests in such collisions are interference effects caused by coherent scattering/interaction of the ion on more than one atomic center[2,3].The studies of ion-molecule collisions have been mainly restricted to homodiatomic molecule(see Ref.[3]and references therein).In the present work,we study double electron capture in collisions between 30,135 keV/u He^2+ions and CO molecules which are accompanied by breakup of CO^2+into C+and O^+fragments.